The present invention relates to an apparatus for removing spatter from an arc welding torch, and more particularly to a device for removing spatter which is adhered to a gas shielded arc welding torch.
One kind of a gas shielded arc welding torch employs a consumable electrode. In this gas shielded arc welding torch employing a consumable electrode, two types of welding have been known. The first type of welding is called CO.sub.2 welding in which carbon dioxide is employed as a shield gas. The second type of welding is metal active gas (MAG) welding in which argon gas is employed as a shield gas. FIG. 1 illustrates an arc welding torch. The torch 10 has a main body 12, a cylindrical member 14 fixed to the main body 12, and a gas nozzle 16. The cylindrical member 14 comprises a large diameter portion 18 and a small diameter portion 20. The large diameter portion 18 of the cylindrical member 14 is fitted into a penetrating hole 22 defined at the central portion of the main body 12, and the portion 18 is fixed to the main body 12. The cylindrical member 14 has a guide hole 24 therein which extends in the longitudinal direction of the cylindrical member 14. A wire, which is employed as a consumable electrode, is designed to be fed through the guide hole 24 from the small diameter portion 20 to the outside. Further, the main body 12 of the torch 10 is provided at its tip end with a hole 28 having a circular cross section whose diameter is larger than the diameter of the penetrating hole 22. The cylindrical gas nozzle 16 is screwed to the tip end of the main body 12, which surrounds the hole 28. The gas nozzle 16 surrounds the cylindrical member 14 therein. The gas nozzle 16 is radially inwardly inclined from its longitudinal intermediate portion to its longitudinal tip end. When a gas shielded arc weld is made, the shield gas supplied from a gas supply device is emitted from a plurality of gas holes 30 which are formed in the large diameter portion 18 of the cylindrical member 14. Further, the injected gas passes through a passage 32 having an annular cross section, defined between the gas nozzle 16 and the cylindrical member 14 and injects from the tip end of the gas nozzle 16 to the outside, thereby shielding the area around the portion where the tip end of the wire 26 and a part of a metal to be welded are melted by the arc generated between the wire 26 and the metal to be welded.
By conducting experiments in which the above-described torch 10 is employed, the following table was obtained, which indicates the amount of the spatter adhered to the torch and the degree of the influence of the spatter on the formation of a blowhole.
______________________________________ AMOUNT POSITION OF OF SPATTER SPATTER TO BE AD- TO BE AD- INFLUENCE ON HERED HERED BLOWHOLE ______________________________________ BOTTOM PORTION OF SMALL SMALL THE HOLE 28 BOUNDARY PORTION MEDIUM MEDIUM BETWEEN THE LARGE DIAMETER PORTION 18 AND THE SMALL DIAMETER PORTION 20 OF THE CYLINDRICAL MEMBER 14 TOP AND LARGE LARGE INNER SUR- FACES OF THE GAS NOZZLE 16 TOP SURFACE OF MEDIUM SMALL THE CYLINDRICAL MEMBER 14 ______________________________________
Once a small amount of spatter adheres, more spatter is inclined to accumulate quickly. If no countermeasure for removing the spatter which has adhered is made, the spatter will disturb the smooth flow of the shield gas. This will cause a blowhole to occur at the portion to be welded which is disadvantageous. From the above table, it is apparent that a medium or large amount of spatter adheres to the boundary between the large diameter portion 18 and the small diameter portion 20 of the cylindrical member 14, and also to the top and inner surfaces of the gas nozzle 16. Thus, spatter adheres to the tip of the passage 32 in a greater quantity than at the gas holes 30. Hence, the flow of shield gas is easily disturbed. This influences the occurrence of a blowhole in metal to be welded considerably. To prevent the blowhole from occurring, it is necessary to clean the torch 10 and remove the spatter which has adhered. According to the prior art approach, the gas nozzle 16 had to be disassembled and the spatter which had adhered had to be removed using an air gun or a brush. This operation took about five minutes for one operation. Further, blowholes occur at irregular intervals and the frequency of occurrence of blowholes was high. Hence, to completely obviate the occurrence of adhered spatter, the number of cleanings has to increase, thus the time for cleaning increases and this lowers the efficiency of operation of the welding equipment.